President Barack Obama joined September 11 survivors, rescuers and relatives of people who lost their lives at the dedication of a memorial museum on the site of the 9/11 attacks in New York. Accounts of extraordinary heroism were recalled from that day. The National September 11 Memorial Museum includes thousands of personal items and parts of the World Trade Center towers themselves. In attendance too were Rudy Giuliani, the New York mayor at the time of the attacks, the present mayor, Bill de Blasio, and actor Robert De Niro. 

Almost 3,000 people died on 11 September 2001 after al-Qaeda hijackers crashed airliners and their passengers into the two towers of the New York Trade Center. Another hijacked plane hit the Pentagon. A fourth crashed into a field in Pennsylvania after passengers fought with the hijackers.